Mechanical and flame retardant performance of fiberglass-reinforced polysilsesquioxane interpenetrated with poly(ethylene glycol)-urethane

Abstract An interpenetrating polymer network (IPN) is designed through sequential optimization. The original polymer network is constructed using rigid polysilsesquioxane (PMPOSS) and styrene, while the second polymer network is composed of flexible poly(hexamethylene diisocyanate) (PHMDI) and poly(ethylene glycol). The designed IPN system, referred to as PMPP, shows a maximum flexural strength that is 272.4% and 94.1% larger than for the PMPOSS-styrene and PMPOSS-styrene-PHMDI systems, respectively. Based on the IPN, fiberglass-reinforced PMPP (GF/PMPP) is further prepared. The peak heat release and smoke production rates are reduced by 62.5% and 69.2%, respectively, compared with those of the PMPP, indicating that the composite has improved heat resistance and smoke suppression performance. Additionally, the flexural strength, thermal conductivity, and dielectric loss of GF/PMPP are 276 MPa, 432.2 mWm−1K−1, and 0.015, respectively, illustrating its potential usage in electronic applications.